Charmed

``He would do whatever he had to do to claim the dukedom and everything that went with it-including Lady Philipa Chauncey. And when she discovered his reason for pursuing her, she would hate him.'' That pretty neatly sums up the plot of Cameron's satisfying historical offering. The duke in question is Calum Innes, switched at birth by his father's mistress, who replaced Calum with her own child, then ordered Calum's death. Rather than kill him, the baby's appointed kidnapper left him at the door of Viscount Hunsington, where he was raised with dignity and respect. Thirty-odd years later, Calum, armed with clues to his true birthright, sets out to reclaim his title. Etienne, Calum's changeling, has been betrothed to Lady Philipa since her birth. Lady Philipa succumbs to Calum's advances but, honor-bound to the arranged marriage, refuses his proposal to terminate her engagement to Etienne. Encouraging the lovers-and keeping the story moving along-is Etienne's avaricious, power-hungry mistress, Anabel. Shifting genres is difficult-often disastrous-for many authors, but Cameron, who writes contemporary (Pure Delights) as well as historical romances, seems to accomplish the feat with little effort. Her narrative is rich, her style distinct and her characters wonderfully wicked. (Apr.)